What’s Vulnerable › Vulnerabilities

CVE-2021-20320

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-02-18 · updated 2026-10-08
• Weakness: CWE-200

Description

A flaw was found in s390 eBPF JIT in bpf_jit_insn in arch/s390/net/bpf_jit_comp.c in the Linux kernel. In this flaw, a local attacker with special user privilege can circumvent the verifier and may lead to a confidentiality problem.

Affected products

• Fedoraproject Fedora: 34
• Linux kernel: before 5.15; 5.15, 5.15-rc1, 5.15-rc2 — fixed in 5.15
• Red Hat Enterprise Linux: 7.0, 8.0

How to fix

Upgrade to a fixed version: Linux kernel 5.15. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=2010090
• https://lore.kernel.org/bpf/20210902185229.1840281-1-johan.almbladh%40anyfinetworks.com/
• https://bugzilla.redhat.com/show_bug.cgi?id=2010090
• https://lore.kernel.org/bpf/20210902185229.1840281-1-johan.almbladh%40anyfinetworks.com/

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